professor
Active Member
My reasoning for the belt drive is the chain set-up I had was a bear to pedal without power and I thought that the motor was having to fight all the drag of the idlers, chains and jackshaft- thus sucking up power and range.
I also considered a roller drive but thought the belt was easier to do.
I used a 20 inch bike rim for a wheel "Pulley", 450 watt scooter motor with a 1.5 inch OD v-belt pulley with a 1/2" bore (the pulley is for a half inch belt- called "4L"). I'm using a 3/8 drive belt (this combo makes the belt ride as low as possible in the pulley- to get the drive ratio as low as I can). Had to wrap a twelve thousandths shim between the motor shaft and pulley to take up the difference between the metric shaft and the SAE pulley.
The controller is a 500watt 24v from TNC scooter along with a thumb throttle.
Batteries are 9ah 12v - definitely on the small side but I don't go very far. They are in a rack covered with a plastic bag.
The good- awsomely quiet, the only sound is a very high pitch faint hum from the controller and a slightly noisy idler brg in my belt "clutch"- actuated by a HT clutch lever.
Power is OK, maybe goes 20 mph.
I just went 5 miles and it did loose some power but still good- a lot better than the chain set-up I had.
In the event of any failure, the drive belt can be slipped off eliminating drag- the belt just rolls along next to the wheel.
Very inexpensive to do but I did do quite a bit of fabrication.
The bad- drive belt slips on full throttle when the batteries are full- belt spray (grip) would probably end this. The slippage is on the motor pulley.
The thumb throttle is like a bear trap after a while, I am thinking about putting a counter-operating spring on it to make it lighter.
I had to modify the frame a little to allow for the drive pulley's extra width.
Pics-
I also considered a roller drive but thought the belt was easier to do.
I used a 20 inch bike rim for a wheel "Pulley", 450 watt scooter motor with a 1.5 inch OD v-belt pulley with a 1/2" bore (the pulley is for a half inch belt- called "4L"). I'm using a 3/8 drive belt (this combo makes the belt ride as low as possible in the pulley- to get the drive ratio as low as I can). Had to wrap a twelve thousandths shim between the motor shaft and pulley to take up the difference between the metric shaft and the SAE pulley.
The controller is a 500watt 24v from TNC scooter along with a thumb throttle.
Batteries are 9ah 12v - definitely on the small side but I don't go very far. They are in a rack covered with a plastic bag.
The good- awsomely quiet, the only sound is a very high pitch faint hum from the controller and a slightly noisy idler brg in my belt "clutch"- actuated by a HT clutch lever.
Power is OK, maybe goes 20 mph.
I just went 5 miles and it did loose some power but still good- a lot better than the chain set-up I had.
In the event of any failure, the drive belt can be slipped off eliminating drag- the belt just rolls along next to the wheel.
Very inexpensive to do but I did do quite a bit of fabrication.
The bad- drive belt slips on full throttle when the batteries are full- belt spray (grip) would probably end this. The slippage is on the motor pulley.
The thumb throttle is like a bear trap after a while, I am thinking about putting a counter-operating spring on it to make it lighter.
I had to modify the frame a little to allow for the drive pulley's extra width.
Pics-